A “Payment Agreement” is an essential agreement between the “Homeowner” and Contractor. Once you have the “Quotation Agreement/Schedule” in place, you know the costs and time required to complete your project. The “Payment Agreement” confirms how much the Contractor is paid and when i.e. £12,000 project over 12 weeks might mean a payment of £1000 per week subject to certain works being completed. Alternatively on some projects a deposit may be agreed.
The Contractor is not a bank and should not have to finance your project from his own pocket in the same way you are not expected to pay for work not done.